summaryrefslogtreecommitdiffstats
path: root/perl_checker.src/common.ml
blob: c7fe4031cf192cd312e79e2ceb158db4adefca7c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
open Stack
open List

exception Found
exception Not_comparable
exception GraphSort_circular_deps

type ('a, 'b) either = Left of 'a | Right of 'b
type ('a, 'b) or_option = Or_some of 'a | Or_error of 'b

(**********************************************************************************)

let internal_error s = failwith ("internal error: " ^ s)

let id x = x
let double a = a,a
let swap (x,y) = (y,x)
let safe_tl l = try tl l with _ -> []
let fstfst ((e, _), _) = e
let sndfst ((_, e), _) = e
let fstsnd (_, (e, _)) = e
let sndsnd (_, (_, e)) = e

let fst3 (e, _, _) = e
let snd3 (_, e, _) = e
let ter3 (_, _, e) = e
let sndter3 (_, a, b) = (a, b)

let o f g x = f (g x)
let curry f x y = f (x,y)
let uncurry f (x, y) = f x y

let is_int n = ceil n = n

let uncons = function
  | [] -> failwith "uncons"
  | e::l -> e,l

let has_env var = 
  try 
    let _ = Sys.getenv var in true
  with Not_found -> false

let some = function 
  | Some e -> e
  | None -> failwith "some"

let some_or = function
  | None -> id
  | Some e -> fun _ -> e

let option2l = function
  | None -> []
  | Some e -> [e]

let prefer_some f a b =
  match a, b with
  | Some a, Some b -> Some (f a b)
  | None, _ -> b
  | _, None -> a

let rec collect_accu f accu = function
  | [] -> accu
  | e::l -> collect_accu f (rev_append (f e) accu) l

let collect f l = rev (collect_accu f [] l)

let merge_some merge a b = 
  match a,b with
  | None, None -> None
  | _, None -> a
  | None, _ -> b
  | Some(a), Some(b) -> Some(merge a b)

let rec uniq = function
  | [] -> []
  | e::l -> if mem e l then uniq l else e :: uniq l

let rec uniq_ eq = function
  | [] -> []
  | e::l -> 
      try 
	let _ = find (eq e) l in
	uniq_ eq l
      with Not_found -> e :: uniq_ eq l

let rec non_uniq = function
  | [] -> []
  | e::l -> if mem e l then e :: non_uniq l else non_uniq l

let rec member_ eq e = function
  | [] -> false
  | e'::l -> if eq e e' then true else member_ eq e l

let rec find_some p = function
  | [] -> raise Not_found
  | x :: l -> 
      match p x with
      |	Some v -> v
      |	None -> find_some p l

let fold_left1 f = function
  | [] -> failwith "fold_left1"
  | e :: l -> fold_left f e l

let find_index e l =
  let rec find_index_ i = function
    | [] -> raise Not_found
    | e'::l -> if e=e' then i else find_index_ (i+1) l
  in
  find_index_ 0 l

let rec find_some_ p = function
  | [] -> None
  | x :: l -> 
      match p x with
      |	Some v -> Some v
      |	None -> find_some_ p l

let rec fpartition p l =
  let rec part yes no = function
  | [] -> (rev yes, rev no)
  | x :: l -> 
      (match p x with
      |	None -> part yes (x :: no) l
      |	Some v -> part (v :: yes) no l) in
  part [] [] l

let partition_either f l =
  let rec part_either left right = function
  | [] -> (rev left, rev right)
  | x :: l -> 
      (match f x with
      |	Left  e -> part_either (e :: left) right l
      |	Right e -> part_either left (e :: right) l) in
  part_either [] [] l

let rec keep_best f = 
  let rec partition e = function
    | [] -> e, []
    | e' :: l ->
	match f(e,e') with
	| None -> let (e'', l') = partition e l in e'', e' :: l'
	| Some e'' -> partition e'' l
  in function
  | [] -> []
  | e::l -> 
      let (e', l') = partition e l in
      e' :: keep_best f l'

let rec keep_bests f l = 
  let rec once e unchanged = function
    | [] -> None
    | e' :: l ->
	match f(e,e') with
	| None -> once e (e' :: unchanged) l
	| Some e'' -> Some(e'', unchanged @ l)
  in
  let rec as_many_as_possible e l =
    match once e [] l with
    | None -> None
    | Some(e', l') -> Some(some_or (as_many_as_possible e' l') (e', l'))
  in
  let rec try_with e l_done l_next =
    match as_many_as_possible e l_next with
    | None -> try_with_next (e :: l_done) l_next
    | Some(e2, l_next2) -> 
	match as_many_as_possible e2 l_done with
	| None -> try_with_next (e2 :: l_done) l_next2
	| Some(e3, l_done2) -> try_with e3 l_done2 l_next2
  and try_with_next l_done = function
    | [] -> rev l_done
    | e::l_next -> try_with e l_done l_next
  in
  try_with_next [] l

let rec fold_right1 f = function
  | [] -> failwith "fold_right1"
  | [e] -> e
  | e::l -> f e (fold_right1 f l)

let rec for_all2_ p l1 l2 =
  match (l1, l2) with
    ([], []) -> true
  | (a1::l1, a2::l2) -> p a1 a2 && for_all2_ p l1 l2
  | (_, _) -> false

let rec for_all2_true p l1 l2 =
  match (l1, l2) with
  | (a1::l1, a2::l2) -> p a1 a2 && for_all2_true p l1 l2
  | (_, _) -> true

let maxl l = fold_right1 max l
  
let rec stack2list s =
  let l = ref [] in
  Stack.iter (fun e -> l := e :: !l) s ;
  !l
  
let rec stack_exists f s =
  try
    Stack.iter (fun e -> if f e then raise Found) s ;
    false
  with Found -> true

let rec queue2list q = rev (Queue.fold (fun b a -> a :: b) [] q)

let rec fix_point f p =
  let p' = f p in
  if p = p' then p else fix_point f p'

let rec fix_point_withenv f env p =
  let p', env' = f env p in
  if p = p' then (p, env') else fix_point_withenv f env' p'

let rec fix_point_ nb f p =
  let p' = f p in
  if p = p' then p, nb else fix_point_ (nb+1) f p'

let rec group_by_2 = function
  | [] -> []
  | a :: b :: l -> (a, b) :: group_by_2 l
  | _ -> failwith "group_by_2"

(*
let rec lfix_point f e =
  let e' = f(e) in
  if e = e' then e :: lfix_point f e' else [e]
*)

let do0_withenv doit f env l =
  let r_env = ref env in
  doit (fun e -> r_env := f !r_env e) l ;
  !r_env

let do0_withenv2 doit f env l =
  let r_env = ref env in
  doit (fun e e' -> r_env := f !r_env e e') l ;
  !r_env

let do_withenv doit f env l =
  let r_env = ref env in
  let l' = doit (fun e -> 
    let e', env' = f !r_env e in
    r_env := env' ; e'
  ) l in
  l', !r_env

let do2_withenv doit f env l1 l2 =
  let r_env = ref env in
  let l' = doit (fun e1 e2 -> 
    let e', env' = f !r_env e1 e2 in
    r_env := env' ; e'
  ) l1 l2 in
  l', !r_env

let do_collect doit f l1 =
  let l = ref [] in
  doit (fun i t -> l := f i t @ !l) l1 ;
  !l

let map_withitself f l =
  let rec map_withitself_ done_ = function
    | [] -> done_
    | e :: l -> 
	let e' = f (done_ @ e :: l) e in
	map_withitself_ (done_ @ [ e' ]) l
  in map_withitself_ [] l

let map_t2 f (x,y) = f x, f y
let map_t3 f (x,y,z) = f x, f y, f z
let map_option f = function
  | Some e -> Some (f e)
  | None -> None
let map_optionoption f = function
  | Some e -> f e
  | None -> None
let t2_option2option_t2 = function
  | (Some x, Some y) -> Some(x,y)
  | _ -> None
let rec l_option2option_l = function
  | [] -> Some []
  | None :: _l -> None
  | Some e :: l -> map_option (fun l -> e :: l) (l_option2option_l l)
let map_option_env f (e, env) = map_option f e, env

let t2_to_list (a,b) = [ a ; b ]
let t3_to_list (a,b,c) = [ a ; b ; c ]

let if_some bool val_ = if bool then Some val_ else None

let rec fold_left_option f val_ = function
  | [] -> Some val_
  | e::l ->
      match f val_ e with
      |	None -> None
      |	Some val_' -> fold_left_option f val_' l

let collect_some_withenv f env l = 
  let rec collect accu env = function
    | [] -> rev accu, env
    | e::l -> 
	let e', env' = f env e in
	let accu' = 
	  match e' with 
	  | Some e' -> e'::accu 
	  | None -> accu in
	collect accu' env' l
  in collect [] env l
	  
let for_all_option_withenv remap f env l =
  let rec for_all env accu = function
    | [] -> Some(remap (rev accu)), env
    | e::l ->
	(match f env e with
	| None, env' -> None, env'
	| Some e', env' -> for_all env' (e' :: accu) l)
  in
  for_all env [] l

let for_all2_option_withenv remap f env la lb =
  let rec for_all env accu = function
    | [], [] -> Some(remap (rev accu)), env
    | a::la, b::lb ->
	(match f env a b with
	| None, env' -> None, env'
	| Some ab, env' -> for_all env' (ab :: accu) (la, lb))
    | _ -> None, env
  in
  for_all env [] (la, lb)

let map_or_option f = function
  | Or_some e -> Or_some (f e)
  | Or_error err -> Or_error err

let map_index f l =
  let rec map_ n = function
    | [] -> []
    | e::l -> f e n :: map_ (n+1) l
  in map_ 0 l

let filter_index f l =
  let rec filter_ n = function
    | [] -> []
    | e::l -> 
	let l' = filter_ (n+1) l in
	if f e n then e :: l' else l'
  in filter_ 0 l

let iter_index f l =
  let rec iter_ n = function
    | [] -> ()
    | e::l -> f e n ; iter_ (n+1) l
  in iter_ 0 l

let map_fst f (x, y) = f x, y
let map_snd f (x, y) = x, f y

let map_withenv      f env e = do_withenv map f env e
let find_withenv     f env e = do_withenv find f env e
let filter_withenv   f env e = do_withenv filter f env e
let exists_withenv   f env e = do_withenv exists f env e
let map_t2_withenv   f env e = do_withenv map_t2 f env e
let for_all_withenv  f env e = do_withenv for_all f env e
let collect_withenv  f env e = do_withenv collect f env e
let partition_either_withenv f env e = do_withenv partition_either f env e

let map2_withenv     f env l1 l2 = do2_withenv map2 f env l1 l2
let for_all2_withenv f env l1 l2 = do2_withenv for_all2 f env l1 l2

let rec take n l =
  if n = 0 then []
  else match l with
  | [] -> raise Not_found
  | e::l -> e :: take (n-1) l
let last_n n l = rev (take n (rev l))
let last l = hd (last_n 1 l)

let rec skipfirst e = function
  | [] -> []
  | e'::l when e = e' -> skipfirst e l
  | l -> l

let rec removelast = function
  | [] -> failwith "removelast"
  | [_] -> []
  | e::l -> e :: removelast l

let rec split_last l = 
  let rec spl accu = function
  | [] -> failwith "split_last"
  | [e] -> rev accu, e
  | e::l -> spl (e :: accu) l
  in spl [] l

let iter_assoc_val f l = iter (fun (_,v) -> f v) l
let map_assoc_val f l = map (fun (k,v) -> k, f v) l

let assoc_or_fail e l =
  try assoc e l with Not_found -> failwith "assoc failed"

let assoc_by is_same e l = 
  find_some (fun (a,b) -> if is_same e a then Some b else None) l

let rec update_assoc_by is_same f e = function
  | [] -> raise Not_found
  | (a,b) :: l when is_same e a -> (a, f b) :: l
  | (a,b) :: l -> (a,b) :: update_assoc_by is_same f e l

let update_assoc f e = update_assoc_by (=) f e

let rec update_assoc_by_with_default default is_same f e = function
  | [] -> [ e, f default ]
  | (a,b) :: l when is_same e a -> (a, f b) :: l
  | (a,b) :: l -> (a,b) :: update_assoc_by_with_default default is_same f e l

let update_all_assoc_by is_same f e l =
  map (fun (a,b) -> a, if is_same e a then f b else b) l

let rec rassoc e = function
  | [] -> raise Not_found
  | (k,v) :: l -> if e = v then k else rassoc e l

let rec all_assoc e = function
  | [] -> []
  | (e',v) :: l when e=e' -> v :: all_assoc e l
  | _ :: l -> all_assoc e l

let rec all_assoc_by is_same e = function
  | [] -> []
  | (e',v) :: l when is_same e e' -> v :: all_assoc_by is_same e l
  | _ :: l -> all_assoc_by is_same e l

let prepare_want_all_assoc l =
  map (fun n -> n, uniq (all_assoc n l)) (uniq (map fst l))

let prepare_want_all_assoc_by is_same l =
  map (fun n -> n, uniq_ is_same (all_assoc_by is_same n l)) (uniq_ is_same (map fst l))

let prepare_want_all_assoc_by_ is_same_a is_same_b l =
  map (fun n -> n, uniq_ is_same_b (all_assoc_by is_same_a n l)) (uniq_ is_same_a (map fst l))

let rec count_uniq = function
  | [] -> []
  | e::l -> 
      let has, l' = partition ((=) e) l in
      (e, length has + 1) :: count_uniq l'

let rec repeat e = function
  | 0 -> []
  | n -> e :: repeat e (n-1)

let rec inits = function
  | [] -> [[]]
  | e::l -> [] :: map (fun l -> e::l) (inits l)
let rec tails = function
  | [] -> [[]]
  | (_::xs) as xxs -> xxs :: tails xs

let apply f x = f x;;

let rec map3 f l1 l2 l3 =
  match (l1, l2, l3) with
    ([], [], []) -> []
  | (a1::l1, a2::l2, a3::l3) -> let r = f a1 a2 a3 in r :: map3 f l1 l2 l3
  | (_, _, _) -> invalid_arg "map3"

let filter2 f l1 l2 =
  split (filter f (combine l1 l2))

let break_at f l =
  let rec b l1 = function
  | [] -> l1, []
  | e::l2 -> if f e then (l1, e :: l2) else b (l1 @ [e]) l2
  in b [] l
let break v l = break_at ((=) v) l

let drop_while f l = snd (break_at (fun e -> not (f e)) l)

(* break_at_indice 0 [1;2] gives [], [1;2]
   break_at_indice 1 [1;2] gives [1], [2]
 *)
let rec break_at_indice i l =
  if i = 0 then [], l else
   match l with
   | [] -> raise Not_found
   | e::l2 ->
     let a, b = break_at_indice (i-1) l2 in
     e::a, b

let rev_nth e l =
  let rec rev_nth' i = function
  | [] -> raise Not_found
  | e'::_ when e'=e -> i
  | _::l -> rev_nth' (i+1) l
  in  rev_nth' 0 l

let rec getset_nth l i f =
  match l, i with
  | e::l', 0 -> f e :: l'
  | [], _ -> failwith "getset_nth"
  | e::l', _ -> e :: getset_nth l' (i - 1) f

let set_nth l i v = getset_nth l i (fun _ -> v)
    
let adjustModDown m n = n - (n mod m)
let adjustModUp m n = adjustModDown m (n + m - 1)


let hashtbl_find f h =
  let r = ref None in
  Hashtbl.iter (fun v c -> if f v c then r := Some v) h ;
  match !r with
  | Some v -> v
  | None -> raise Not_found

let hashtbl_map f h = Hashtbl.iter (fun v c -> Hashtbl.replace h v (f v c)) h

let hashtbl_values  h = Hashtbl.fold (fun _ v l -> v :: l) h []
let hashtbl_keys    h = Hashtbl.fold (fun k _ l -> k :: l) h []
let hashtbl_to_list h = Hashtbl.fold (fun k v l -> (k,v) :: l) h []

let hashtbl_collect f h =
  rev (Hashtbl.fold (fun k v l -> rev_append (f k v) l) h [])

let hashtbl_exists f h =
  try
    Hashtbl.iter (fun v c -> if f v c then raise Found) h ;
    false
  with Found -> true

let memoize f =
  let hash = Hashtbl.create 16 in
  fun k ->
    try Hashtbl.find hash k
    with Not_found ->
      let v = f k in
      Hashtbl.add hash k v ; v

let array_shift a = Array.sub a 1 (Array.length a - 1)
let array_last_n n a = 
  let len = Array.length a in
  Array.sub a (len - n) n

let array_collect f a = Array.fold_left (fun l e -> f e @ l) [] a

let rec lvector_product = 
  let rec vector_product a b = match a with
  | [] -> []
  | e::l -> map (fun e' -> e :: e') b :: vector_product l b
  in function
  | [] -> []
  | [e] -> map (fun e -> [e]) e
  | e::l -> flatten (vector_product e (lvector_product l))

let vector_product2 a b =
  map (function
  | [a;b] -> a,b
  | _ -> failwith "vector_product2"
  ) (lvector_product [ a ; b ])

let rec transpose = function
  | [] :: _ -> []
  | ll -> 
      let l, ll' = split (map (function e::l -> e,l | _ -> raise Not_found) ll) in
      l :: transpose ll'

let rec range min max =
  if min >= max then [] else min :: range (min + 1) max

let sum l = List.fold_left (+) 0 l

let rec filter_some_with f = function
  | [] -> []
  | e :: l -> 
      match f e with
      |	None -> filter_some_with f l
      | Some e' -> e' :: filter_some_with f l

let rec filter_some = function
  | [] -> []
  | None :: l -> filter_some l
  | Some e :: l -> e :: filter_some l

let rec difference l = function
  | [] -> l
  | e::l' -> difference (filter ((<>) e) l) l'

let rec difference_ eq l = function
  | [] -> l
  | e::l' -> 
      let l2 = filter (fun e' -> not (eq e e')) l in
      difference_ eq l2 l'

let intersection_by is_same l1 l2 = filter (fun e -> exists (is_same e) l2) l1

let intersection_and_differences eq l1 l2 =
  let rec both inter l2_only = function
    | [], l2 -> inter, [], rev l2_only @ l2
    | l1, [] -> inter, l1, rev l2_only
    | l1, e2 :: l2' ->
	match partition (eq e2) l1 with
	| [], _ -> both inter (e2 :: l2_only) (l1, l2')
	| _, l1' -> both (e2 :: inter) l2_only (l1', l2')
  in both [] [] (l1, l2)

let rec triangularize = function
  | [] -> []
  | e::l -> (e,l) :: triangularize l

let diagonalize l =
  map_index (fun a i ->
    a, filter_index (fun _ j -> i <> j) l
  ) l

let rec list_of_nonempty_sublists = function
  | [] -> []
  | e :: l -> 
      let l' = list_of_nonempty_sublists l in
      [e] :: l' @ map (fun l -> e :: l) l'

let rec graph_is_sorted_by eq = function
  | [] -> true
  | (_,deps) :: l -> 
      for_all (fun e -> try let _ = assoc_by eq e l in false with Not_found -> true) deps && graph_is_sorted_by eq l

let graph_closure_by eq graph =
  let err = ref None in
  try
    let graph_rev = collect (fun (i, l) -> map (fun e -> (e, i)) l) graph in
    let bothway = map (fun (i,l) -> i, (l, all_assoc_by eq i graph_rev)) graph in
    let closed = fold_left (fun graph j ->
        let next, prev = assoc_by eq j graph in
        let graph2 = fold_left (fun graph i ->
        if member_ eq i next then (err := Some(j,i); raise GraphSort_circular_deps) else
        update_assoc_by eq (fun (i_next,i_prev) -> i_next @ next, i_prev) i graph
      ) graph (filter (fun a -> not (eq a j)) prev) in
      let graph3 = fold_left (fun graph k ->
        if member_ eq k prev then (err := Some(j,k); raise GraphSort_circular_deps) else
        update_assoc_by eq (fun (k_next,k_prev) -> k_next, k_prev @ prev) k graph
      ) graph2 (filter (fun a -> not (eq a j)) next) in
      graph3
    ) bothway (map fst bothway) in
    Or_some (map (fun (e,(next,_)) -> e, uniq_ eq next) closed)
  with GraphSort_circular_deps ->
    Or_error (some !err)

let rec graph_sort_by eq l =
  let cmp (_, deps_a) (b, _) = if member_ eq b deps_a then 1 else -1 in 
  let rec sort_it = function
    | [] -> []
    | [e] -> [e]
    | e::l ->
	let l' = sort_it l in
	let gt, lt = break_at (fun ((_, deps) as e') -> deps = [] or cmp e e' = 1) l' in
	gt @ [e] @ lt
  in 
  map_or_option (fun l' ->
    let l_sorted = rev (sort_it l') in
    if not (graph_is_sorted_by eq l_sorted) then internal_error "graph_sort failed" else
    l_sorted
  ) (graph_closure_by eq l)

let int_sort l = sort (fun a b -> a - b) l

let str_begins_with s prefix =
  String.sub s 0 (min (String.length s) (String.length prefix)) = prefix

let rec strstr s subs =
  let len_s, len_subs = String.length s, String.length subs in
  let rec rec_ i =
    let i' = String.index_from s i subs.[0] in
    if i' + len_subs <= len_s then
      if String.sub s i' len_subs = subs then
	i'
      else
	rec_ (i' + 1)
    else
      raise Not_found
  in
  rec_ 0

let str_contains s subs =
  try
    let _ = strstr s subs in true
  with Not_found -> false

let str_ends_with s suffix =
  let len = min (String.length s) (String.length suffix) in
  String.sub s (String.length s - len) len = suffix

let chop = function
  | "" -> ""
  | s -> String.sub s 0 (String.length s - 1)

let chomps s =
  let i = ref (String.length s - 1) in
  while !i >= 0 && (s.[!i] = ' ' || s.[!i] = '\t') do decr i done ;
  String.sub s 0 (!i+1)

let rec times e = function
  | 0 -> []
  | n -> e :: times e (n-1)

let skip_n_char_ beg end_ s =
  let full_len = String.length s in
  if beg < full_len && full_len - beg - end_ > 0 
  then String.sub s beg (full_len - beg - end_)
  else ""
let skip_n_char n s = skip_n_char_ n 0 s

let rec non_index_from s beg c =
  if s.[beg] = c then non_index_from s (beg+1) c else beg
let non_index s c = non_index_from s 0 c

let rec non_rindex_from s beg c =
  if s.[beg] = c then non_rindex_from s (beg-1) c else beg
let non_rindex s c = non_rindex_from s (String.length s - 1) c

let rec explode_string = function
  | "" -> []
  | s -> (String.get s 0) :: explode_string (String.sub s 1 (String.length s - 1))

let count_matching_char s c =
  let rec count_matching_char_ nb i =
    try
      let i' = String.index_from s i c in
      count_matching_char_ (nb+1) (i'+1)
    with Not_found -> nb
  in
  count_matching_char_ 0 0

let is_uppercase c = Char.lowercase c <> c
let is_lowercase c = Char.uppercase c <> c

let char_is_alphanumerical c =
  let i = Char.code c in
  Char.code 'a' <= i && i <= Char.code 'z' ||
  Char.code 'A' <= i && i <= Char.code 'Z' ||
  Char.code '0' <= i && i <= Char.code '9'

let char_is_alphanumerical_ c =
  let i = Char.code c in
  Char.code 'a' <= i && i <= Char.code 'z' ||
  Char.code 'A' <= i && i <= Char.code 'Z' ||
  Char.code '0' <= i && i <= Char.code '9' || c = '_'

let char_is_alpha c =
  let i = Char.code c in
  Char.code 'a' <= i && i <= Char.code 'z' ||
  Char.code 'A' <= i && i <= Char.code 'Z'

let char_is_number c =
  let i = Char.code c in
  Char.code '0' <= i && i <= Char.code '9'

let count_chars_in_string s c =
  let rec rec_count_chars_in_string from =
    try
      let from' = String.index_from s from c in
      1 + rec_count_chars_in_string (from' + 1)
    with
      Not_found -> 0
  in rec_count_chars_in_string 0

let rec string_fold_left f val_ s =
  let val_ = ref val_ in
  for i = 0 to String.length s - 1 do
    val_ := f !val_ s.[i]
  done ;
  !val_

(*
let rec string_forall_with f i s =
  try
    f s.[i] && string_forall_with f (i+1) s
  with Invalid_argument _ -> true
*)
let string_forall_with f i s =
  let len = String.length s in
  let rec string_forall_with_ i =
    i >= len || f s.[i] && string_forall_with_ (i+1)
  in string_forall_with_ i

let starts_with_non_lowercase s = s <> "" && s.[0] <> '_' && not (is_lowercase s.[0])

let rec fold_lines f init chan =
  try 
    let line = input_line chan in 
    fold_lines f (f init line) chan
  with End_of_file -> init
let readlines chan = List.rev (fold_lines (fun l e -> e::l) [] chan)

let split_at c s =
  let rec split_at_ accu i =
    try
      let i' = String.index_from s i c in
      split_at_ (String.sub s i (i' - i) :: accu) (i'+1)
    with Not_found -> rev (skip_n_char i s :: accu)
  in
  split_at_ [] 0

let split_at2 c1 c2 s =
  let rec split_at2_ accu i i2 =
    try
      let i3 = String.index_from s i2 c1 in
      if s.[i3+1] = c2 then split_at2_ (String.sub s i (i3 - i) :: accu) (i3+2) (i3+2) else
      split_at2_ accu i i3
    with Not_found | Invalid_argument _ -> rev (skip_n_char i s :: accu)
  in
  split_at2_ [] 0 0

let words s =
  let rec words_ accu i s =
    try
      let i2 = non_index_from s i ' ' in
      try
	let i3 = String.index_from s i2 ' ' in
	words_ (String.sub s i2 (i3 - i2) :: accu) (i3+1) s
      with Not_found -> rev (skip_n_char i2 s :: accu)
    with Invalid_argument _ -> rev accu
  in
  collect (words_ [] 0) (split_at '\n' s)

let to_CamelCase s_ =
  let l = ref [] in
  let s = String.copy s_ in
  for i = 1 to String.length s - 1 do 
      if is_uppercase (String.unsafe_get s i) && is_lowercase (String.unsafe_get s (i-1)) then (
	String.set s i (Char.lowercase (String.get s i)) ;
        l := i :: !l
      )
  done ;
  if !l = [] then None else
  let offset, s' = fold_left (fun (offset, s') i -> 
    i, s' ^ String.sub s offset (i-offset) ^ "_"
  ) (0, "") (rev !l) in
  Some (s' ^ String.sub s offset (String.length s - offset))

let concat_symlink file link =
  if str_begins_with link "..//" then (* ..//foo => /foo *)
    skip_n_char 3 link
  else
    let file = if str_ends_with file "/" then chop file else file in (* s|/$|| *)
    let rec reduce file link =
      if str_begins_with link "../" then
	let file = String.sub file 0 (String.rindex file '/') in (* s|/[^/]+$|| *)
	reduce file (skip_n_char 3 link)
      else
	file ^ "/" ^ link
    in
    reduce file link

let expand_symlinks file =
  match split_at '/' file with
  | "" :: l ->
      let rec remove_dotdot accu nb = function
	| [] -> if nb = 0 then accu else failwith "remove_dotdot"
	| ".." :: l -> remove_dotdot accu (nb + 1) l
	| e :: l -> if nb > 0 then remove_dotdot accu (nb - 1) l else remove_dotdot (e :: accu) nb l
      in
      let l = remove_dotdot [] 0 (List.rev l) in
      List.fold_left (fun file piece ->
	fix_point (fun file -> 
	  try concat_symlink file ("../" ^ Unix.readlink file) 
	  with _ -> file
        ) (file ^ "/" ^ piece)) "" l
  | _ -> internal_error (Printf.sprintf "expand_symlinks: %s is relative\n" file)

let mtime f = (Unix.stat f).Unix.st_mtime

let rec updir dir nb =
  if nb = 0 then dir else
  match dir with
  | "." -> String.concat "/" (times ".." nb)
  | _ -> 
      if Filename.basename dir = ".." then
	dir ^ "/" ^ String.concat "/" (times ".." nb)
      else
	updir (Filename.dirname dir) (nb-1)

let (string_of_ref : 'a ref -> string) = fun r ->
  Printf.sprintf "0x%x" (Obj.magic r : int)

let print_endline_flush_quiet = ref false
let print_endline_flush s = if not !print_endline_flush_quiet then (print_endline s ; flush stdout)
let print_endline_flush_always s = print_endline s ; flush stdout

let is_int n = n = floor n

(* total order *)
let rec compare_lists cmp l1 l2 =
  match l1, l2 with
  | [], [] -> 0
  | [], _ -> -1
  | _, [] -> 1
  | e1::l1, e2::l2 ->
      match cmp e1 e2 with
      |	0 -> compare_lists cmp l1 l2
      |	v -> v

let compare_best a b =
  match a, b with
  |  0,  0 -> 0
  |  1,  1 |  1, 0 | 0,  1 ->  1
  | -1, -1 | -1, 0 | 0, -1 -> -1
  |  1, -1 | -1, 1 -> raise Not_comparable
  | _ -> failwith "uh?"

(* partial order *)
let combine_comparison_list l =
  fold_left compare_best 0 l

let min_with_cmp less_than a b =
  if less_than a b then a
  else if less_than b a then b
  else raise Not_comparable

let max_with_cmp less_than a b =
  if less_than a b then b
  else if less_than b a then a
  else raise Not_comparable

let rec fold_left2_compare f e l1 l2 =
  match l1, l2 with
  | [], [] -> e
  | e1::l1, e2::l2 -> fold_left2_compare f (f e e1 e2) l1 l2
  | _ -> raise Not_comparable

let rec exists_compare cmp = function
  | [] -> raise Not_comparable
  | e :: l -> try cmp e with Not_comparable -> exists_compare cmp l

let forall_compare cmp = fold_left (fun n e -> compare_best n (cmp e)) 0
let forall2_compare cmp = fold_left2_compare (fun n e1 e2 -> compare_best n (cmp e1 e2)) 0

let exists2_compare left_dropping cmp l1 l2 =
  let rec forall_compare_ n = function
    | [], [] -> n
    | _, [] -> compare_best n left_dropping
    | [], _ -> compare_best n (-left_dropping)
    | e1::l1, e2::l2 ->
	match try Some (cmp e1 e2) with Not_comparable -> None with
	| Some n' -> forall_compare_ (compare_best n n') (l1, l2)
	| None ->
	    if n = left_dropping then
	      forall_compare_ left_dropping (l1, e2::l2)
	    else if n = -left_dropping then
	      forall_compare_ (-left_dropping) (e1::l1, l2)
	    else
	      (* need to try both *)
	      try forall_compare_ left_dropping (l1, e2::l2)
	      with Not_comparable -> forall_compare_ (-left_dropping) (e1::l1, l2)
  in forall_compare_ 0 (l1, l2)


let rec compare_sorted_sets is_same l1 l2 =
  match l1, l2 with
  | [], [] -> 0
  | [], _ -> -1
  | _, [] -> 1
  | e1::l1, e2::l2 -> if is_same e1 e2 then compare_sorted_sets is_same l1 l2 else raise Not_found

let scan_list_while_modifying f l =
  let rec scan_list_while_modifying_ prev = function
    | [] -> prev
    | e :: next -> 
	let prev', next' = some_or (f prev next e) (prev @ [e], next) in
	scan_list_while_modifying_ prev' next'
  in scan_list_while_modifying_ [] l

let bools2compare = function
  | true, true -> 0
  | true, false -> -1
  | false, true -> 1
  | _ -> raise Not_comparable

let lpush l e = l := e :: !l

(*
let is_greater2compare is_greater a b =
  match is_greater a b, is_greater b a with

  *)

module OrderedString =
  struct
    type t = string
    let compare = compare
  end;;

module StringSet = Set.Make(OrderedString);;

let stringSet_to_list = StringSet.elements
let stringSet_add set e = StringSet.add e set
let stringSet_difference = StringSet.diff
let list_to_StringSet l = fold_left stringSet_add StringSet.empty l